Fan



Sept- 30 1924;

C. W. JOHNSON FAN Filed Dec. '30, 1913 WETNESSES g v MJMW mar/w W Johnson v n I MZ- Y Patented Sept. 30, 1924.

UNITED STATES CHARLES W. JOHNSON, OF PITTSBURGH,

VANIA.

PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- FAN.

Application filed December 30, 1918. Serial No. 268,793.

.T 0 all whom it may concern:

Be it known that I, CHARLES W. J onnson, a citizen of the United States, and a resi- -dent of Pittsburgh, in the county of Allegheny and State of Pennsylvania,- have invented a new and useful Improvement in Fans, of which the following is-a specification.

My invention relates to fans or blowers and more particularly to electric fans in which a plurality of substantially oval and transversely concavo-convex blades extend radially from a rotatable hub or spider. One of the primary objects of my invention resides in the provision of a novel type of blade possessing numerous advantages over the blades now in use in fan .structures of this character.

Electric fans, as now made, are provided either with brass or with steel blades whichare stamped, punched or otherwise shaped and are riveted to a metallic spider. At the present time, the metal employed in constructin such blades is expensive and can be1 obtamed only with considerable diflicu ty.

One of the objects of my invention resides in the provision of fan blades corre-' sponding, in shape and operation, to those now in use but formed of fibrous material impregnated with a suitable binder and compacted, hardened and stifi'ened by molding or curing in any suitable manner.

The wide use of fans, as now constructed, has developed certain inherent defects or objections, elimination of which, up to the present time, has appeared impossible. For

example, fan blades of either brass or steel are relatively heavy and are easily damaged, by being bent out of shape or deformed, by rough handling of the fan containers during shipment or by carelessness either in of the fans or in their subsequent hand ing. Any bending out of shape of the fan blades not only renders the fan noisy but, if occurring to a material extent, imposes such undue strains upon the motor as to cause severe wearing ofitsbearings which will, in time, render it noisy also. Even if such deformation of one or more of the blades is noted, it is almost impossible to bend the damaged blade or blades to original shape, so that there is practically no remedy other than complete replacement.

above enumerated difliculties by the employment of a novel material, never before used for the purpose, which may preferably comprise superlmposed sheets of fibrous material impregnated with a binder which will harden, an example of which is bakelite or an equivalent condensation product.

Through actual tests, it has been found that a fan of the usual type, except that its blades are constructed of impregnated fibrous material, will overcome practically all of the objections common to the metal fans now used. The blades of a fan so constructed areextremely light, having substantially one-half the specific. gravity of aluminum and, for this reason, there is practically no likelihood of producin unbalanced fan which, in any way, con (1 be harmful to its driving motor. Furthermore, blades of this material, because of their resiliency and their relatively low period of vibration, which is far below that period of vibration which is from 30% to 45% less than that of brass, which has hitherto been considered the preferable material for fan blades.

Because of the lightness of the blades, the fans may be more economically shipped and, on account of their resiliency, they are practically immune to rough handlin and consequent injury. Furthermore,in t e ordinary course of their construction, they are given a highly finished and smooth surface which will offer small air resistance.

'In addition to the foregoing mechanical advantages possessed by Ian blades constructed in accordance with my-invent lon such blades are also desirable because 0 their ornamental appearance, as the blades are translucent and. may be readily given any desired color to harmonize with the Moreover, a an having metal In orde to insure a clear and accurate understandin of my invention, I have illustrated a pre erred a plication of it in the drawings in which ig. 1 is a front elevationof a fan embodying my invention, and Fig. 2 is a sectional view. of one of the blades the section being taken on the line 11-1130: Fi 1.

As here own, my improved fan may comprise a plurality of blades 1, of conventional shape and proportions, secured by rivets 2, or other desirable fastenin means, to'the radial extending arms 3 of t e usual hub or spider 4 which, in practice, is generally mounted directly upon one end of a motor-driven shaft.

My invention resides in the material and method employed in constructing:l the blades 1, and it is best illustrated in t e sectional view shown in Fig. 2. The blade, as here indicated, comprises a plurality of superimposed layers 5 of fibrous sheet material impregnated wit a hardened binder.

In practicing 'm invention, I may impregnate a suitable fi rous sheet material, such as paper, woven fabric, cotton batting or other'fabricated material, with any desired binder, such as a shellac substitute. For example, a phenolic condensation product may be desirably employed as the binder an if it is employed, the sheet material after impregnation with the dissolved binder, ma be heated to. a sufficient extent to drive 0 the solvent without converting the binder to its hard, insoluble, final state.

The material so treated may be cut to provide blanks of the proper sha e and these blanksmay be superimposed to orm a body of suitable thickness for the construction of a fan blade, or a plurality of treated sheets may be superimposed to the proper thickness and blade-forming blanks may be cut therefrom. After the assembled blanks have been obtained in any suitable manner, they may be cured by the simultaneous application of heat and pressure by any suitable means, care bein taken that the blanks are given the proper s iape, during their curing, by hardening them in molds or by any other equivalent means.

Qbviously, if a fan is to be constructed in which the blades are flat, a fully cured and hardened plate of fibrous sheet material impregnated with a binder may be employed,

and the finished blanks may be'stamped, punched or otherwise formed from this plate. Fan blades formed by an of the oregoing methods are extreme y light,

incorporating any suitable dye, pigment or other coloring material in the impregnating agent emplo ed, it is possible to give the finished bla es various desirable colors in order that they may harmonize, in appearance, with the remaining portion of the fan or with surrounding ob ects.

The molding or curin of the blades automatically insures hig ly polished and smooth surfaces having very slight skin friction and, therefore, ofierlng but small resistance to the air.

Inasmuch as I have described several modifications of the method of forming the fan blades and because of the fact that the blades may be made in various shapes and sizes and that any desired number of blades may be mounted on a common hub or spider, it will be apparent that various modifications are possible and, therefore, my present invention is to be in no way restricted except as indicated in the claims.

I claim as my invention:

1. A fan including a hub and a plurality of fan blades secured thereto, the blades each comprising fibrous material impregnated with a hardened binder.

2. A fan including a hub and a pluralitv of fan blades secured thereto, the blades each comprising fibrous sheet material impregnated with a hardened phenolic condensa tion product.

3. A fan blade comprising superimposed layers of fibrous sheet material impregnated with a hardened condensation product.

4. A fan blade comprising a substantially oval, transversely concavo-convex. body of fibrous sheet material impregnated with a hardened phenolic condensation product.

5. A fan blade comprising a molded body of fibrous material and a h at-hardened binder and having a period or vibration which is low relatively to those of brass and steel.

In testimony whereof, I have hereunto subscribed my name this 20th day of Dec... 1918.

CHARLES W. JOHNSON. 

